Plastic electroplating barrel

ABSTRACT

A polyhedral rotatable electroplating barrel having axial ribs and end heads made of a thermoplastic in which fiberglass strands are embedded beneath the outer surfaces thereof to provide support members having high deflection temperatures, tensile and flexural strengths and perforate panels made of a filled thermoplastic resin whose deflection temperature approaches that of the material for the ribs and heads and means interconnecting the ribs, heads and panels whereby a good load-supporting barrel is provided which is resistant to attack by the electroplating solutions and will not distort at operating temperatures of about 180*-200*F.

United States Patent 1 Noonan [4 1 Oct. 23, 1973 I PLASTIC ELECTROPLATING BARREL [75] Inventor: Walter F. Noonan, Wallingford, Pa.

[73] Assignee: Westlake Plastics Company, Lenni,

[22] Filed: July 31, 1972 [2]] Appl. No.: 276,564

Related U.S. Application Data [63] Continuation-impart of Ser. No. 150,985, June 8,

1971, Pat. NO. 3,716,470.

[52] U.S. Cl ..240/213, 118/418, 134/159, 259/89 [51] Int. Cl C23b 5/78 [58] Field of Search 204/213, 214; 118/418; 134/159; 259/89, 90; 260/41 [56] References Cited UNITED STATES PATENTS 3,084,916 4/1963 Schaviner et al. 259/89 3,442,783 5/1969 Kirkpatrick et al 204/213 3,668,103 6/1972 Singleton 204/214 3,716,470 2/1973 Noonan 204/213 FOREIGN PATENTS OR APPLICATIONS 10/1966 Great Britain 260/41 Primary Examiner-F. C. Edmundson Att0rneyMax R. Millman [57] ABSTRACT A polyhedral rotatable electroplating barrel having axial ribs and end heads made of a thermoplastic in which fiberglass strands are embedded beneath the outer surfaces thereof to provide support members having high deflection temperatures, tensile and flexural strengths and perforate panels made of a filled thermoplastic resin whose deflection temperature approaches that of the material for the ribs and heads and means interconnecting the ribs, heads and panels whereby a good load-supporting barrel is provided which is resistant to attack by the electroplating solutions and will not distort at operating temperatures of about 180200F.

11 Claims, 5 Drawing Figures 1 PLASTIC ELECTROPLATING BARREL This application is a continuation-in-part of my copending application Ser. No. 150,985, filed June 8, 1971, now U.S. Pat. No. 3,716,470, and relates generally to electroplating barrels or cylinders in which many small articles are plated at one time and in particular to rotary polyhedral (referred to in the industry as polygonal) barrels with perforated panels through which the electroplating solution is pumped due to rotation thereof.

Heretofore, "polygonal barrels have been fabricated of such materials as hard rubber, polypropylene and methyl methacrylate polymers to resist the corrosive effects of the plating solutions, hard rubber at relatively high operating temperatures in the order of magnitude of 225F., methyl methacrylate at temperatures not exceeding 180F., and polypropylene at operating temperatures in the range of l75-212F., as indicated in the Nielson US. Pat. No. 3,256,170.

The most widely used material at present is polypropylene because it possesses relatively good loadsupport and operating temperature characteristics and is economical to fabricate into the barrel parts. The sides of the barrel are perforate panels secured between axially extending ribs which are in turn secured to end heads or flanges. One of the sides is removably clamped in place to serve as a door. All of these parts are made of polypropylene whose deflection temperature at a load of 264 psi is in the order of magnitude of l35-l40F.

A most common practice is to weld the perforate panels to the ribs. It is also common to operate the barrels at temperatures above that recommended, that is at l80200F., which causes the distortion of the ribs and plates in particular, since these are thinner than the ribs and heads, with the result that the door cannot be removed. The distortion can also rupture the welds securing the plates to the ribs and to the heads.

It is therefore an object of this invention to provide an economical plastic polygonal barrel in which the aforesaid disadvantages of panel distortion and possible weld rupture are minimized while improving the strength of the barrel.

Another important object of the invention is to provide a polygonal electroplating barrel in which the axial ribs and end heads are made of a fiber glass filled thermoplastic resin having a high deflection temperature, tensile and flexural strength-and perforate panels supported by the ribs and heads which are made of a filled thermoplastic resin whose deflection temperature approaches that of the fiber glass filled resin, the deflection temperatures of both resins being such that when the barrel is operated in the range of 180200F. heat distortion of the ribs, plates and heads will be substantially minimized.

Another object of the invention is to provide a polygonal electroplating barrel in which the ribs and heads are made of fiber glass filled polypropylene and the perforate plates are made of mineral filled polypropylene whose deflection temperature, tensile and flexural strengths exceed that of straight polypropylene so that the barrel has good load-supporting properties but can be operated in the range of l80200F. with substantially no heat distortion of the side plates and heads.

Another object of the invention is to provide a polygonal barrel as above described in which the fiber glass strands are embedded in the resin used to make the ribs and heads in such a manner that they are below the surface of said members to minimize their attack by fluorides.

In a preferred embodiment of the invention the axially extending ribs and end heads are made of a glass filled polypropylene and the perforate panels are made of asbestos or talc-filled polypropylene, the ribs each including axially extending angulated grooves receiving the side edges of the panels, the heads being provided at their inner faces with recesses to receive the ends of the ribs and connected by grooves to receive the ends of the panels, the heads being ultimately secured to the ribs and the panels being secured to the ribs and heads so that the barrel has good load-supporting properties and when the barrel is operated in the range of l-200F. distortion of the panels relative to the ribs and heads is substantially eliminated.

These and other objects of the invention will become more apparent as the following description proceeds in conjunction with the accompanying drawings, wherein:

FIG. 1 is a longitudinal sectional view through the electroplating barrel made in accordance with the invention;

FIG. 2 is an end elevational view thereof looking from the line 22 of FIG. 1;

FIG. 3 is a sectional view taken on the line 3-3 of FIG. 1;

FIG. 4 is an enlarged sectional view of a portion of a rib and head illustrating the manner in which the fiber glass strands are embedded in the resin beneath the surface thereof; and

FIG. 5 is an end view of the inner face of a head.

Specific reference is now made to the drawings in which similar reference characters are used for corresponding elements throughout.

The polyhedral barrel, usually hexahedral, but which can have more or less than six sides, is shown generally at 10 and is intended to be suspended by suitable hangers from an overhead rail and rotated horizontally while partially immersed in an electroplating solution. See Electroplating Engineering Handbook, Second Edition, by Graham et al., Chapter 25, entitled Barrels. Conventionally such a barrel consists essentially of panels 12 having perforations l4 therethrough, nonperforate axially extending ribs 16 to which the panels are connected and generally circular end plates, heads or flanges 18 and 20 securing the ribs. The end plates or heads are provided with the usual bearing bosses 22 to suspend the barrel by hangers (not shown) from an overhead rail (not shown), the bosses having bores to provide access for electrodes (now shown) into the barrel.

To rotate the barrel, a gear is associated with one of the heads 20 which is engaged by another gear driven by a suitable overhead motor. In the form of the invention shown, a separate toothed gear wheel 24 is bolted as at 26 to the head 20 with spacers 28 intervening between the head 20 and gear wheel 24. In another conventional form of invention the head itself is provided with peripheral gear teeth. In yet another form of invention no gears are used. Rather, the head is in the form of a pulley having a peripheral groove for engagement by a belt to be driven thereby.

The perforate panels form the faces of the polyhedron except that for one face the panel 38 serves as a door for access to the interior of the barrel. As seen in FIG. 3, the door is generally thicker than the panels, is removably supported on the adjacent ribs 40 and 42 and there retained by suitable clamping devices 44 well known in the art. See, for example, the Neilson U.S. Pat. No. 3,256,l70.

The ribs 16 and heads 18 and 20 are made of a thermoplastic resin having good tensile and flexural strength and a deflection temperature under load so that the ribs and heads will not distort until a temperature of about 260F. is attained. It has been found that polypropylene filled with -20 percent by weight of fiber glass strands is economical to mold into the ribs and heads, has excellent tensile and flexural strength and deflection temperatures at 264 psi of about 280305F. The glass filled resin is molded in such a manner that the fibers 46 extend beneath the outer surfaces 48 and 50 of the ribs and heads to leave areas 52 and 54 which are free of the glass fibers or strands, thus minimizing attack on the faces of the ribs and heads which may be exposed to fluorides, as seen in FIG. 4.

If the perforate panels 12 were made of a thermoplastic resin such as virgin polypropylene (unmodified homopolymer resin) whose deflection temperature at 264 psi is in the order of magnitude of l35l40F., under the loads encountered in electroplating and because of fatigue and other factors, such polypropylene panels would distort in the range of operating temperatures of l80-200F., especially towards the upper range.

Thus the perforate panels 12 are made of mineral filled thermoplastic resins whose deflection temperatures are higher than that of virgin polypropylene and have better flexural and tensile strengths to improve the load-support of the panels. Examples of such materials are asbestos-filled polypropylene sold by Hercules Powder as pro-fax 66FIA which has a deflectitm temperature at 264 psi of about 190 F. and a filler content of 20-40 percent by wt.; and talc-filled polypropylene sold by Hercules Powder as pro-fax 66F3 which has a deflection temperature at 264 psi of about 177F. and about the same filler content; and titanium dioxide-filled polypropylene which has a deflection temperature at 264 psi of about 220F. and a filler content of to 25 percent by wt., preferably 25 percent. The titanium dioxide filler is available from the DuPont Co. as Fibex (potassium titanate). panels 12 of the same fiberglass-filled polypropylene as that used for the ribs and heads, as then all the parts will have the same deflection temperature, coefficient of expansion, flexural and tensile strengths, the making of the panels with this fiberglass-filled polypropylene presents difficulties. Thus, the perforate panels are thinner than the ribs and heads and require many perforations 14. Machining such perforations works havoc on drill bits, even carbide-tipped bits, and if the holes are machined, the glass fibers are exposed and are attackable by fluoride plating solutions.

As will be seen in FIG. 3, the ribs 40 and 42 which support the removable door 38 are molded to contain angulated axially extending grooves 56 in their opposed sides which permits the door to slip into the grooves and rest on the inner walls 58 of the grooves.

Since the door 38 contains many perforations 59, like the perforate panels, it is also made of talc-filled or asbestos-filled polypropylene to secure the advantages of a higher deflection temperature and better tensile and flexural strength than virgin polypropylene. The use of the same fiberglass-filled resin for the door as for the ribs and heads would present the same difficulties in drilling and glass expore noted hereinbefore.

Each rib 16 extends axially between the heads 18 and 20 and constitute the apices or corners of the polyhedron. While ribs may have any desired profile, a substantially rectangular cross-section is desired with bevels 60 at the interior surface thereof to minimize sharp edges which may injure the items to be plated as they tumble in the electroplating solution during rotation of the barrel. Opening through the opposite axially extending sides 62 and 64 of each rib are substantially U- shaped grooves 66 and 68 which extend at angles to each other equivalent to the interior angle required for completion of the polyhedron when the perforate panels are inserted therein as shown in the drawings.

The end of each panel is received in a rib groove and is secured to the ribs by suitable welds (not shown) or other equivalent means.

As seen in FIG. 5, the inner surface 82 of each head 18 and 20 is provided with recesses 84 approximating the cross-sectional dimensions and configurations of the ribs 16 and recesses 86 and 88 approximating the cross-sectional dimensions and configurations of the door ribs 40 and 42. Interconnecting the recesses 84 are grooves 90 which approximate the dimensions and configurations of the panels 12. A further wider groove 92 which approximates the cross-sectional dimensions and configurations of the door interconnects the recesses 86 and 88. When the ends of the ribs are received in their respective recesses 84, 86 and 88 and the ends 92 of the panels in their respective grooves 90, the heads 18 and 20 are then secured as by bolts 94 to the ribs.

The heads are so molded that the recesses 84, 86 and 88 and grooves 90 and 92 are confined to that portion of each head which is free of the glass fibers 46, that is a portion like the areas 52 and 54 shown in FIG. 4. The same applies to the rib grooves 66 and 68.

After the ends of the ribs and perforate panels are received in their corresponding recesses 84, 86 and 88 and grooves 90, they are secured to the heads by welds (not shown) or other equivalent means.

While a preferred embodiment has here been shown and described, it is understood that a skilled artisan may make minor variations without departing from the spirit of the invention.

What is claimed is:

1. A polyhedral electroplating barrel comprising axially extending perforate panels made of a mineral-filled thermoplastic resin whose deflection temperature exceeds that of a virgin polypropylene and forming the sides of the barrel, axially extending ribs forming the corners thereof and supporting said panels and end heads supporting the ends of said panels and ribs, said ribs and said heads being made of a fiberglass-filled thermoplastic resin whose deflection temperature exceeds that of the panel material.

2. The barrel of claim 1 wherein said fiberglass-filled resin is polypropylene containing glass strands embedded therein having surface areas which are free of the glass strands. I

3. The barrel of claim 2 wherein the polypropylene contains lO-20 percent by weight of the fiberglass strands having a deflection temperature at 264 psi of about 280305F.

4. The barrel of claim 2 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is asbestos-filled polypropylene.

5. The barrel of claim 3 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is asbestos-filled polypropylene having a deflection temperature at 264 psi of about 190F.

6. The barrel of claim 2 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is talc-filled polypropylene.

7. The barrel of claim 3 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is talc-filled polypropylene having a deflection temperature at 264 psi of about 177F.

8. The barrel of claim 2 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is titanium dioxide-filled polypropylene.

9. The barrel of claim 3 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is titanium dioxide-filled polypropylene having a deflection temperature at 264 psi of about 220F.

10. A polyhedral electroplating barrel comprising axially extending perforate panels made of mineral-filled polypropylene and forming the sides of the barrel, axially extending ribs forming the corners of the barrel and having grooves opening at the included angle of the polyhedron through the sides of each rib and receiving the side edges of said panels and end heads having interconnected recesses and grooves opening through their inner surfaces and corresponding to and receiving the ends of said ribs and panels respectively, said ribs and heads being made of fiberglass-filled polypropylene wherein the strands of fiberglass are embedded in the polypropylene so that surface areas are free of the strands, the grooves in the ribs and the recesses and grooves in the heads being provided in the surface areas thereof which are free of the fiberglass strands.

11. The barrel of claim 10 wherein the fiberglassfilled polypropylene includes 10-20 percent by weight of fiberglass and a deflection temperature at 264 psi of about 280-305F.

gg g TED STATES PATEN OVLFFICE TEFKQATE GRIEQ'HUN Patent No. ,76 Dated October 23,1973.v

Inventofls) I Walter O nan It is certified vthat error appears in the. above-identifiedpaterit and that said Letters Patent are hereby corrected as shown belew:

Col. 3, between lines 46 and 4?, insert:

While it may appear desirable to make the perforatem Signed and sealed this 19t h day ofv February 1974;

(SEAL) I Attes I l r 5DwARD M.FLETcHER,J-RQ MARSHALL AN v Attestlng Offwer v I Commissioner pf-Patents 

2. The barrel of claim 1 wherein said fiberglass-filled resin is polypropylene containing glass strands embedded therein having surface areas which are free of the glass strands.
 3. The barrel of claim 2 wherein the polypropylene contains 10-20 percent by weight of the fiberglass strands having a deflection temperature at 264 psi of about 280*-305*F.
 4. The barrel of claim 2 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is asbestos-filled polypropylene.
 5. The barrel of claim 3 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is asbestos-filled polypropylene having a deflection temperature at 264 psi of about 190*F.
 6. The barrel of claim 2 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is talc-filled polypropylene.
 7. The barrel of claim 3 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is talc-filled polypropylene having a deflection temperature at 264 psi of about 177*F.
 8. The barrel of claim 2 wherein the minEral-filled thermoplastic resin of which the perforate panels are made is titanium dioxide-filled polypropylene.
 9. The barrel of claim 3 wherein the mineral-filled thermoplastic resin of which the perforate panels are made is titanium dioxide-filled polypropylene having a deflection temperature at 264 psi of about 220*F.
 10. A polyhedral electroplating barrel comprising axially extending perforate panels made of mineral-filled polypropylene and forming the sides of the barrel, axially extending ribs forming the corners of the barrel and having grooves opening at the included angle of the polyhedron through the sides of each rib and receiving the side edges of said panels and end heads having interconnected recesses and grooves opening through their inner surfaces and corresponding to and receiving the ends of said ribs and panels respectively, said ribs and heads being made of fiberglass-filled polypropylene wherein the strands of fiberglass are embedded in the polypropylene so that surface areas are free of the strands, the grooves in the ribs and the recesses and grooves in the heads being provided in the surface areas thereof which are free of the fiberglass strands.
 11. The barrel of claim 10 wherein the fiberglass-filled polypropylene includes 10-20 percent by weight of fiberglass and a deflection temperature at 264 psi of about 280*-305*F. 